This invention pertains to wood lathes, and more particularly, it pertains to an apparatus and a method for turning cylindrical posts and rails on a bandsaw mill.
Since the late seventies, the use of portable bandsaw mills has known a continuous growth in North America. These machines are convenient for sawing lumber out of a few logs for a private wood lot owner, as well as for sawing several thousand board feet per day at a commercial forest product operation. These machines are transportable on wheels behind a pickup truck between wood lots, or are simply set on blocks at a log yard and left there for readily sawing harvested logs into lumber. The machines are relatively easy to operate and to maintain. The ratio of their production capacities over capital investment is attractive to a contractor. Therefore, these machines have created a new lumber industry, where wood lot owners do not have to transport their logs to distant sawmills.
In such on-site forest product operation, however, it is sometime desirable to manufacture round wood shafts for use as posts, railings, and in building log houses and lawn ornaments, for examples. In the past, it was not possible to manufacture round wood shafts on a bandsaw mill because of a lack of machinery suitable for this purpose.
It is believed that the prior art is short of suggestions with regard to a machine to manufacture round shafts on a bandsaw mill. It is also believed that the prior art is short of suggestion with regard to a method for turning a round shaft using any bandsaw machine. Therefore, the bandsaw mill operators of the past were lacking the means and the incentive to consider the manufacturing of round wood shafts from clients"" logs.
As such, it may be appreciated that there continues to be need for a lathe attachment for a bandsaw mill, which can take advantage of the cutting edge of a bandsaw blade and the power advance system of the bandsaw head to produce round shafts on a job site, as easily as the conventional production of lumber.
In the present invention, there is provided a lathe attachment for installation on a portable bandsaw mill, for turning round shafts on that portable bandsaw mill. The lathe attachment according to the present invention comprises broadly, an elongated chassis, a tailstock and a headstock mounted on opposite ends of the elongated chassis; a live centre and a driven spindle on the tailstock and headstock respectively for holding and rotating a wood block along the elongated chassis. The lathe attachment also comprises bindings for retaining the elongated chassis to the cross beams of a portable bandsaw mill.
The lathe attachment is usable to make round posts, wood columns, logs for log houses, fencing stock, and other round wood products of the like on a portable horizontal bandsaw mill.
In another aspect of the present invention, the lathe attachment comprises an indexing mechanism on the driven spindle, for positioning and holding the driven spindle at various angular positions. This indexing mechanism is advantageous for sawing a number of symmetrical facets along a wood block prior to turning the wood block.
In yet another aspect of the present invention, there is provided a method for turning a round shaft on a bandsaw mill, which consists of:
using a bandsaw blade, sawing a number of symmetrical facets along an elongated wood block at a same diameter on the wood block, such that the facets enclose the circumference of the elongated wood block;
while operating the bandsaw blade in a first direction, rotating the wood block about its longitudinal axis in a second direction opposite the first direction; and
moving the bandsaw blade along the wood block, at the mentioned diameter of the wood block for turning the wood block into a round shaft having the mentioned diameter.
In yet another aspect of the present invention, the turning of the round shaft on the bandsaw mill is effected while the alignment of the wood block makes an acute angle with the direction of movement of the bandsaw head. This oblique alignment is advantageous for reducing wobbling of the bandsaw blade during the turning of a round shaft.
Still another feature of this lathe attachment is that it is susceptible of a low cost of manufacture with regard to both materials and labour, and which accordingly is then susceptible of low price of sale to the consumer, thereby making such lathe attachment economically available to the public.
Other advantages and novel features of the present invention will become apparent from the following detailed description.